[MEX-966] xoxno aggregator integration

[claudiulataretu]

Reasoning

• The auto-router only evaluated internal xExchange liquidity when computing optimal swap routes, missing potentially better quotes from external aggregators
  • XOXNO aggregator can route through multiple DEXes and liquidity sources, offering better output amounts for certain token pairs
  • Users should always receive the best possible output regardless of which DEX provides the liquidity

Proposed Changes

• Add XoxnoAggregatorService to fetch quotes and ready-to-sign transactions from the XOXNO API, with error isolation and fallback behavior
• Extend AutoRouterService to fetch XOXNO and internal quotes in parallel, then select the route with the highest amountOut
• Add SmartSwapSource enum (INTERNAL | XOXNO) attached to SmartSwapModel so callers know which route was selected
• Introduce SmartSwapPairModel as a DEX-agnostic replacement for PairModel in SmartSwapRoute.pairs, carrying address, dex, firstToken, and secondToken
• Store the raw XOXNO amountOut on AutoRouteModel for observability and comparison
• Add getXoxnoAggregatorEnabled() feature flag in RemoteConfigGetterService for runtime toggling of the integration
• Re-fetch a fresh XOXNO quote at transaction-build time to ensure the signed transaction is up-to-date; fall back gracefully to internal routing on any error
  • Add unit tests for XoxnoAggregatorService and integration/spec tests for the updated swap-selection logic in AutoRouterService

How to test

• Enable the XOXNO_AGGREGATOR feature flag in remote config
• Call the swap GraphQL query for a token pair where XOXNO offers a better rate; verify smartSwap.source returns xoxno
  • Disable the flag or point to an unreachable XOXNO endpoint and confirm the service falls back to internal routing without errors

[codecov]

Codecov Report

❌ Patch coverage is 85.33333% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 53.84%. Comparing base (0433a2b) to head (1335498).
⚠️ Report is 20 commits behind head on development.

Files with missing lines	Patch %	Lines
...ules/remote-config/remote-config.getter.service.ts	0.00%	8 Missing ⚠️
src/helpers/api.config.service.ts	0.00%	5 Missing ⚠️
...auto-router/mocks/xoxno-aggregator.service.mock.ts	50.00%	4 Missing ⚠️
...odules/auto-router/services/auto-router.service.ts	95.52%	3 Missing ⚠️
...s/auto-router/services/xoxno-aggregator.service.ts	97.61%	1 Missing ⚠️
...uation/services/smart.router.evaluation.service.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           development    #1746      +/-   ##
===============================================
+ Coverage        53.51%   53.84%   +0.33%     
===============================================
  Files              298      300       +2     
  Lines            14601    14749     +148     
  Branches          1903     1980      +77     
===============================================
+ Hits              7813     7941     +128     
+ Misses            6782     6485     -297     
- Partials             6      323     +317     

Flag	Coverage Δ
unittests	53.84% <85.33%> (+0.33%)	⬆️

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